Fine grain silver halide photographic emulsion containing hemicyanine sensitizing dye

ABSTRACT

A HEMICYANINE DYE IS USED TO SPECTRALLY SENSITIZE SILVER HALIDE PHOTOGRAPHIC EMULSIONS TO PRODUCE EMULSIONS HAVING HIGH PHOTOSENSITIVITY IN THE REGION OF WAVELENGTHS OF ABSORPTION INTRINSIC TO SILVER HALIDE AND IN THE REGION OF WAVELE WAVELENGTHS OF THE DYE.

United States Patent Office 31,788,859 Patented Jan. 29, 1974- US. Cl. 96139 8 Claims ABSTRACT OF THE DISCLOSURE A hemicyanine dye is used to spectrally sensitize silver halide photographic emulsions to produce emulsions having high photosensitivity in the region of wavelengths of absorption intrinsic to silver halide and in the region of wavelengths of the dye.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to a spectrally sensitized silver halide photographic emulsion, in particular, to a silver halide photographic emulsion of fine grains having remarkably high photosensitivity in the region of wavelengths of absorption intrinsic to silver halile, not only in the region of the absorption wavelengths of a sensitizing dye, by spectrally sensitizing with hemicyanine dye.

(2) Prior art It is well known in the art of producing silver halide photographic emulsions that the region of photosensitive wavelength of silver halide emulsions can be extended by adding a certain kind of sensitizing dye to the silver halide emulsion. Generally, however, when the silver halide emulsion containing silver halide crystals, whose size is that used in the production of normal silver halide photographic sensitive material, is spectrally sensitized, the photosensitivity in the region of wavelengths of absorption intrinsic to silver halide is lowered. This well known phenomenon is called densensitization. Therefore, sensitizing dyes having small desensitizing actions of this kind are desired in the selection of sensitizing dyes used in the production of silver halide photographic sensitive materials. On the other hand, it is preferable to make the grain size of silver halide crystals contained in the silver halide emulsion as small as possible in order to improve the image quality such as resolving power, state of grains therein, etc., obtained from the silver halide photographic sensitive material. However, this lowers the sensitivity of the photographic material in general.

Accordingly, in the field of correlated arts, the art to make the grain size of silver halide crystals as small as possible and to prepare a silver halide emulsion having sufficient sensitivity has resulted in chemical sensitization such as sulfur sensitization or reduction sensitization and the like, becoming a necessity.

Capri-blue effect is known as another phenomenon of a rise in photosensitivity by sensitizing dyes in the region of absorption intrinsic to silver halide. However, the Capri-blue effect is the phenomenon which appears at the short time expose with high illuminance when desensitizing or sensitizing dyes are added to the silver halide emulsion which have not been sensitized with sulfur or have not undergone reduction sensitization.

(3) Objects of the invention An object of the present invention is to obtain a silver halide photographic emulsion whose photosensitivity in the region of wavelengths of absorption intrinsic to silver halide is remarkably raised in addition to the region of wavelengths of sensitivity thereof being extended.

Other objects will be apparent to those skilled in the art as the description of this invention proceeds.

BRIEF SUMMARY OF THE INVENTION The elfect found by this invention is quite different from the aforestated Capri-blue in that the photosensitivity of the silver halide in the region of wavelengths of absorption intrinsic to silver halide is remarkably raised by adding a hemicyanine dye to the emulsion containing silver halide crystals of certain size even when this emulsion is sensitized by the sulfur sensitization, reduction sensitization or gold sensitization, and that this effect is especially great in long time exposure.

We have found that when silver halide emulsion containing silver halide crystals at least by number of which is no more than 0.2 micron in diameter or silver halide emulsion containing silver halide crystals whose mean particle diameter by number is no more than 0.18 micron is spectrally sensitized in the usual way using hemicyanine dye, the photosensitivity of the silver halide in the region of wavelengths of absorption intrinsic to silver halide can be remarkably raised in addition to the region of wavelengths of sensitivity of the dye used being extended.

DETAILED DESCRIPTION OF THE INVENTION The above-mentioned objects are accomplished by adding at least one of the hemicyanine dyes having the following general Formula I or II to a silver halide emulsion containing silver halide crystals 95% by number of which is no more than 0.2 micron in diameter or to a silver halide emulsion. containing silver halide crystals whose mean particle diameter by number is no more than 0.18 microns:

wherein Z represents a group of atoms necessary to complete a fiveor six-membered heterocyclic nucleus, such as oxazoline, thiazoline, oxazole, thiazole, selenazole, benzoxazole, benzothiazole, benzoselenazole, naphthoxazole, naphthothiazole, indolinine, imidazol, benzimidazole, naphthiomidazole, pyridine, quinoline nucleus, etc., which may be substituted, R represents lower alkyl group such as methyl, ethyl, n-propyl, hydroxyalkyl (e.g. betahydroxyethyl, beta-methoxyethyl), acetoxyalkyl (such as beta-acetoxyethyl), an alkyl group containing a carboxy group (such as beta-carboxyethyl, gamma-caboxypropyl, delta-carboxybutyl, omega-carboxypentyl, p-carboxyphenylethyl), an alkyl group containing a sulfo group (such as beta-sulfoethyl, gamma-sulfopropyl, 'gamma-sulfobutyl, delta-sulfobutyl, p-sulfophenylethyl), vinylmethyl, an aralkyl (such as benzyl and phenylethyl),and the like, A represents a hydrogen atom or, when taken together with B, represents a group of atoms necessary to complete a ring, preferably containing at least one heterocyclic atom connected through a polymethylene chain, such as morpholine, pyr'rolidine, piperazine, and piperadine, B represents an aryl group (such as phenyl, tolyl, etc.) or, when taken together with A, represents a group of atoms necessary to complete a ring, L represents a methine chain or L and R may be connected with each other through a polymethylene chain, X represents anion such as usually salt thereof is formed.

as phenyl, tolyl group, etc.

Representative hemicyanine dyes used in this invention 5 are illustrated as follows, but are not limited wherein Z, R, L, m and n are the same meanings as those in the general Formula I, B represents an aryl group, 'such Dye 19...-

Dye 20..::

Dye 22:

Dye 23..=

Dye 24":

Dye 25":

Dye 26...:

DYB 27..::

Cam

TABLE Contlnued Dye 28..-:

Dye 29":

The sensitizing dyes used in this invention represented by the general Formula I or II can be readily prepared according to the procedure described for example, in the specification of the British Pat. No. 355,693, or U.S. Pat. Nos. 2,298,732 and 2,369,509.

The hemicyanine dyes used in this invention are capable of not only extending the wavelength region of sensitivity of the photographic emulsion, but at the same time, raising the photosensitivity of silver halide in the region of wavelengths of absorption intrinsic to silver halide, when used in combination with a photographic emulsion containing silver halide crystals at least 95% by number of which is no more than 0.2 micron in diameter or with a photographic emulsion containing silver halide crystals whose mean particle diameter by number is no more than 0.18 micron.

This is especially eflective for a gelatin-silver halide emulsion, but it is also elfective for a silver halide emulsion containing a hydrophilic colloid other than gelatin, such as agar-agar, collodion, water-soluble cellulose derivative or synthetic or natural hydrophilic resins such as polyvinylalcohol, etc.

Silver halide photographic emulsions used in this invention may be any of silver chloride, silver bromochloride, silver bromide, and silver bromiodide emulsion, but especially excellent eifect is obtained in the case of silver bromide or silver bromiodide emulsions.

The sensitizing efliect of the hemicyanine dyes in this invention to the region of wavelengths of absorption intrinsic to silver halide largely depends on the grain size of silver halide crystals. Even between the photographic emulsions having the same halogen composition, the sensitizing eifect differs according to the grain size of silver halide crystals. Especially, in the case of a photographic emulsion containing silver halide crystals whose mean particle diameter by number is more than 0.18 micron, the sensitizing efiectin the region of wavelengths of absorption intrinsic to silver halide decreases greatly.

An example using the hemicyanine dye (18) is given below in Table 1:

TABLE 1 Mean particle diameter (11.) 0.07 0.1 0.15 0.20 0.60 Sensitization ratio 5.0 3 1.3 1.0 0.45

The sensitization ratio is given as the ratio based on the sensitivity value without adding the hemicyanine dye to the silver halide emulsion, which is calculated as 1.

It can be understood from Table 1 that the influence of the grain size of the silver halide crystal is quite great.

In order to prepare spectrally sensitized photographic emulsions according to this invention, one or several of the sensitizing dyes are added in a usual manner to a silver halide photographic emulsion previously sensitized by the chemical sensitization using one or more of unstable sulfur compoundsfprecious metal complex compounds and reducing compounds.

In practice, the hemicyanine dye is usually dissolved in a suitable solvent such as methanol, ethanol, etc., then added to an emulsion. The amount of the hemicyanine dye contained in an emulsion can be varied widely in the range of from 5 mg. to 500 mg. per 1 kg. of emulsion according to the desired effect.

The photographic emulsions of this invention can further be hypersensitized and supersensitized.

The photographic silver halide emulsions of this invention are, for example, employed for IC plate, holography, electrobeam records, etc.

In the production of the photographic emulsions of this invention, conventional additives such as other chemical sensitizing agents, stabilizers, anti-fogging agents, tone-adjusting agents, hardeners, surface active agents, plasticizers, antistatic agents, lubricants, development ac celerators, color couplers and fluorescent brightening agents can be used together in a conventional manner.

This invention will be further explained by the following example.

Photographic emulsions were prepared by adding the hemicyanine dyes given in Table 3 to silver bromiodide emulsion (AgI:AgBr=1 molz99 mols). The resulting emulsions were coated on the film base of cellulose triacetate and dried, which were then exposed to 1000 lux electric light (2666 K.) through Wratten No. 47B filter and developed. The developer having the composition described in Table 2 was used.

TABLE 2 G. Metol 2 Hydroquinone 8.8 Anhydrous sodium sulfite u 96 Anhydrous sodium carbonate 48 Potassium bromide 5 Water, enough to make 1 liter.

TABLE 3 Amount of dye Mean Mean added] parti- Sensi- Comparti- Sensikg. emulole tizapare16 tiza- Ex. Dye sion,mol- Emuldiamtion ison dlamtion No. No. gram slon eter ratio mark eter ratio 1 10-5/6 AgBrI 0.07 3.0 a 0.6 0. 50 2 10-5/ AgBrI 0.07 3.2 b 0.6 0. 45 3 10-5 AgBrI 0.07 3.4 0.6 0. 49 4 105 6 AgBrI 0.07 3.0 d 0.6 0.46 6 10- AgBrI 0.07 3.1 e 0.6 0.45 6 10-5 6 AgBrI 0.07 3.0 t 0.6 0.48 7 10-5/6 .AgBrI 0.07 g 0.6 0.30 8 -5/6 AgBrI 0.07 4.5 11 0.6 0.80 9 10-5 AgBrI 0. 07 4.5 1 0.6 0. 75 10 10-5 6 AgBrI 0.07 4.0 1 0.6 0.55 11 10*5/6 AgBrI 0. 07 42 k 0.6 0.42 12 10-6/6 AgBrI 0.07 4.2 1 0.6 0.48 13 10- 6 AgBrI 0. 07 4.5 m 0.6 0.37 14 105 6 AgBrI 0.07 3.7 n 0.6 0.48 15 105 6 AgBrI 0.07 3.0 O 0.6 0.40 16 10-5 .AgBrI o. 07 4.0 p 0.6 0. 45 17 10-5/6 AgBrI 0. 07 4.5 q 0.6 0.50 18 10-5 6 AgBrI 0. 07 5.0 r 0.6 0.45 19 10-5/6 AgBrI 0. 07 4.2 s 0.6 0.45 20 10-5/6 AgBrI 0.07 3.6 t 0.6 0.48 21 10-5/6 AgBrI 0.07 4.6 u 0.6 0.46 22 10-5 6 AgBrI 0. 07 4.0 v 0.6 0.46 23 10-5/6 AgBrI 0.07 4.5 w 0.6 0.46 24 10-5/6 .AgBrI 0.07 5.0 x 0.6 0.45 25 10-5/6 AgBrI 0.07 4.8 y 0.6 0.40 26 10- 6 AgBrI 0.07 4.0 2 0.6 0.37 27 10-5 6 AgBrI 0. 07 4.2 a 0.6 0.35 28 10-5/6 AgBrI 0.07 4.0 b 0.6 0.42 29 5 AgBrl 0. 07 4.5 0' 0.6 0.14 30 10-5/6 AgBrI 0.07 4.0 d 0.6 0.38

What is claimed is: O 1. A silver halide photographic emulsion comprising 30 at least one of the hemicyanine dyes represented by the g CH=CH OH=CH NH following general Formulae I or II and silver halide crys- H tals, at least 95% by number of which are no more than 0.2 micron in diameter, or whose mean particle diameter I by number is no more than 0.18 micron: 2

S --z A g I OH=OH-CH=CHNH- R-N= cn-o11)=- L=L m-N H Q l B 40 N 's) zH I" wherein Z represents a group of atoms necessary to com- S plete a fiveor six-membered heterocyclic ring, R repree sents a. lower alkyl group, A represents a hydrogen atom, CH B represents an aryl group, or A and B taken together CH=CH CH=CH NH* may represent groups of atoms necessary to complete a ring containing at least one heterocyclic atom connected through a polymethylene chain, L represents a 0113i methine chain such that L and R may be connected with 0 each other through a polymethylene chain, X represents an anion, m represents 1, 2 or 3, n represents 0 or 1, p represents 0 or 1, and 11:0 if an intramolecular salt HCCH CH OH NH thereof is formed;

I, --Z zHs I. R--N(OH=CH)nC=(L-L)m=NB (II) 8 wherein Z, R, L, n and m are the same meanings as those in general Formula I, B represents an aryl group.

2. The emulsion according to claim 1 wherein said dye is selected from the group consisting of 1 S Se 4 6H, -on=on-on=on-Nn- -on=on-on=on-Nnand 3. The emulsion according to claim 1 wherein said Z is selected from the group consisting of oxazolines, thiazolines, oxazoles, thiazoles, selenazoles, benzoxazoles, benzothiazoles, benzoselenozoles, naphthoxazoles, naphthothiazoles, indolinines, imidazoles, .benzimidazoles, naphthoimidazoles, pyridines, and quinolines.

4. The emulsion according to claim 1 wherein said R is selected from the group consisting 'of methyl, ethyl, n-propy1,'hydroxyalkyl, acetoxyalkyl, alkyl groups con taining a carboxy group, alkyl groups containinga sulfo group, vinylmethyl and aralkyl groups 5. The emulsion according to claim 1 wherein X is selected from the group consisting of chloride, bromide, iodide, and perchlorate.

6. The emulsion according to claim 1 wherein the amount of said dye in the emulsion is in the range of 5-500 rug-per 1 kg. of emulsion. 7

7. The emulsion according-to claim 1 wherein said emulsion also contains at least one member selected from the group consisting of chemical stabilizing agents, stabilizers, anti-fogging agents, tone adjusting agents, hardeners, surface active agents, plasticizers, antistatic agents, lubricants, development accelerators, color couplers and fluorescent brightening agents.

8. The emulsion according to claim 1 wherein said ring containing at least one heterocyclic 'atom is selected from the group consisting of morpholine, pyrrolidine, piperazine, and piperadine. Y

References Cited UNITED STATES PATENTS 3,038,800 6/1962 Luckey et a1. 96140 3,482,981 12/1969 Van Lare 96-140 3,615,635 10/1971 Shiba et al. 96140 3,575,704 4/1971 -Sa1esin -1. 96-94 3,652,280 3/ 1972 De Belder et al. 96--94 3,661,592 5/1972 Philippaerts et al. 96--94 3,415,650 12/1968 Frame et al. 96-94 3,600,167 8/1971 Judd et a1. 96-94 3,706,566 12/ 1972 Shiba et a1. 96-139 NORMANHG, TORCHIN, Primary Examiner R. L. SCHILLING, Assistant Examiner US. Cl. X.R. 96l40 

